User:Robertinventor/Simple animals could live in Martian brines - Extended Interview with planetary scientist Vlada Stamenković: Difference between revisions

==Interview==

 

Wikinews asked him whether their research suggests potential for life as active as the Earth animals that can survive at similar oxygen levels.

[[File:WOA09 sea-surf O2 AYool.png|thumb|Shows how the oxygen dissolved in Earth's sea surface compares with these predicted values for Mars. From the World Ocean Atlas 2009, the values for the annual mean sea surface concentrations range from below 0.2 to above 0.4 moles per cubic meter (6.4 to 12.8 mg / liter). Values on Mars could range up to 0.2 moles per cubic meter for calcim perchlorate, and up to 2 moles per cubic meter for magnesium perchlroate, in extremely cold brines at the poles. {{Image source|Plumbago}}|alt=]]

 

'''''(background information):''''' Life gets slower and slower at lower temperatures to the point where individual microbes have lifetimes of millennia. Such life is hard to study. It's almost impossible to tell whether it is a) active and able to reproduce at those temperatures or b) active and not able to reproduce, or c) intermittently sometimes active and sometimes dormant. The reproduction can't be studied using cell counts. But the usual limit cited is -20&nbsp;°C<!-- see discussion in A new analysis of Mars "Special Regions" -->. That's well above the lowest temperatures studied in the paper which go down to -133&nbsp;°C.

 

<!-- This para summarizes the Schulze-Makuch paper in the background information section -->

The other possibility is that microbes can continue to function at very low temperatures in the Martian conditions. After the interview I discovered that they go into this in section ''"3.2 The lower temperature limit for life and the potential of aerobic habitats"'' in the supplementary information.

 

 

[[File:MarsOxides.jpg|thumb|Curiosity's discovery image for the manganese-oxide minerals at a location called "Windjana,". These require abundant water and strongly oxidizing conditions to form. With the new theory these conditions may be present on Mars today, previously thought to be only possible on early Mars.]]

 

Their research also helps to explain the presence of some minerals on the Mars surface, such as manganese oxides which require conditions of water and oxygen to form. Some researchers hav suggested they formed in an early Mars atmosphere that was thick and oxygen rich (which doesn't require life; it could for instance be oxygen rich due to ionizing radiation splitting water). This new reseach shows that these minerals could also form without an oxygen rich atmosphere.

::'''VS''': Our explanation doesn't need any special magic — it works on Mars today,

 

 

The paper is theoretical and is based on a simplified general circulation model of the Mars atmosphere - it ignores distinctions of seasons and the day / night cycle. But it takes account of topography (mountains, craters etc) and the axial tilt. They combined it with a chemical model of how oxygen would dissolve in the brines and used this to establish predicted oxygen levels in the brines at the various locations on Mars.

 

'''''(background information):''''' Their model took account of the tilt of the Mars axis, which varies much more than for Earth (our axis is stabilized by the presence of the Moon). They found that for the last five million years conditions were particularly favorable for oxygen rich brines, and that it continues like this for ten million years into the future, as far as they ran the model. For the last twenty million years, as far back as they took their modeling, oases with enough oxygen for sponges are still possible.

 

Remarkably, as they say in the paper, present day Mars would have more oxygen available for life than early Earth had prior to 2.35 billion years ago. On Earth, photosynthesis seems to have come first, before complex multicellular life, generating the oxygen for the first animals. On Mars, with a different source for oxygen, oxygen breathers could arise before photosynthesis. They suggest in their paper that this gives broader opportunities for oxygen-breathing life on other planets.

::'''VS''': 45 deg is approx. the correct degree. We were also tempted to speculate about this temporal driver but realized that we still know so little about the potential for life on Mars/principles of life that anything related to this question would be pure speculation, unfortunately.

[[File:Mars-water-droplets-phoenix-2008-bg.gif|thumb|Unfortunately, the Phoenix lander wasn't equipped to analyze droplets on its legs, which it observed in 2008-9. However, they appear to be droplets of some liquid, most likely salty water, from the way they behaved. These may be our first spacecraft observations of liquid brines on Mars. Nilton Renno's team's research in the University of Michigan's newly built Mars simulation chamber, published in 2014, was able to duplicate them in minutes when salt lies on top of ice. They suggested that such droplets may be common place on Mars today. Wikinews asked Vlada Stamenković if these droplets could be oxygen rich. He said he doesn't know yet, but it is a really good question.]]

 

<!-- This para summarizes material in the "Liquid Water from Ice and Salt on Mars" article in the NASA Astrobiology magazine in the sources -->

::'''VS''': Just like the answer above. Dynamics is still to be explored. (But this is a really good question 😉).

[[File:Mars-SubglacialWater-SouthPoleRegion(cropped).jpg|thumb|Possible 20-km wide subglacial lake close to the Martian south pole. The dark blue region in the overlayed scans, lower middle, is thought to be a radar bright echo from extremely cold brines, probably magnesium and calcium perchlorates at a depth of 1.5 km. Vlada Stamenković et al's model would suggest high solubility for oxygen for these brines too, and he suggested oxygen could get into them through {{w|Radiolysis|radiolysis}} from natural radioactivity of the rocks below.]]

Wikinews also asked how their research is linked to the recent discovery of possible large subglacial lake 1.5 km below the Martian South Pole found through radar mapping.

 

 

'''''(background information):''''' So, his answer here is that it could be possible by the same process, radiolysis of the ice through radioactivity in the rocks.

 

<!-- Next para based on Scientific American article-->

 

''"The report highlights the need to include in situ detection of energy-starved or otherwise sparsely distributed life such as chemolithotrophic or rock-eating life. In particular, the report found that NASA should focus on research and exploration of possible life below the surface of a planet in light of recent advances that have demonstrated the breadth and diversity of life below Earth’s surface, the nature of fluids beneath the surface of Mars, and the likelihood of life-sustaining geological processes in planets and moons with subsurface oceans."''

 

Vlada Stamenković is working on a new instrument TH2OR to send to Mars on some potential future mission. It would search for potentially habitable brines deep below its surface using ultra low frequency radio waves. This is a frequency far lower than that of ground penetrating radar, in the range of a fraction of a Hertz up to kilohertz. Wavelengths are measured in kilometers up to tens of thousands of kilometers or more. Wikinews asked him for more details